Mentally struggling with sex

A week ago me and my boyfriend got into an argument about how I am usually left unsatisfied during sex. I also expressed to him that I feel like it’s always about him during sex and that I feel like he isn’t attracted to me anymore. Before we started dating I would eat maybe once every 2-3 days sometimes longer, after we started dating he made sure I ate every day. So I gain weight. Therefore I thought he wasn’t attracted to me. He assured me that wasn’t the case and apologized that I was left unsatisfied most the time. Since then he hasn’t not touched me or hardly looked at me.

Fast forward to last night.

He was kissing all over me and things started to get pretty intense. However, I just couldn’t mentally get into it. So I asked him to stop. Of course he asked what was wrong and I have no clue how to explain to him that it’s just a mental thing. I feel like there are somethings we still need to work out, and as cheesy as this sounds I want some romance. We never do anything as a couple anymore, I can’t tell you the last time we went on a date. I just want to feel important to him again. I want to feel beautiful to him again.

I don’t know how to explain it to him without starting an argument.